Heterosexual transmission represents a rapidly growing mode of HIV transmission in the United States and a primary mode of transmission worldwide. Young adult women and men accounted for 48 percent and 9 percent, respectively, of AIDS diagnoses in the US between 1999-2000. Over 4.2 million South Africans are currently infected with HIV; over half are younger than 24 years of age, signaling the urgent need to address risk factors for young heterosexual adults. Women's greater risk of infection and relative disempowerment with regard to men are critical factors influencing transmission, placing gender issues in the forefront of the HIV prevention challenge. Gender scripts, which specify culturally influenced standards of appropriate roles for women and men, guide behavior and communication in heterosexual interactions. Therefore, it is critical to understand how these gender scripts compromise women's and men's ability to communicate, negotiate and enact safer sexual behavior; yet methods to assess gender scripts for sexual interactions have not been developed. The aims of this study are thus 1) to use qualitative methods to collect narratives from young adult women and men about sexual interactions in their primary relationships; 2) to use the qualitative data to inform the development of psychometrically sound, theoretically-based measures that will assess gender scripts; and 3) to establish the ways in which gender scripts in sexual interactions and other aspects of gender are associated with participation in sexual risk behaviors. Parallel methodological work will be carried out in New York and South Africa to tailor gender script measures for young adults at high risk for contracting HIV and to learn more about how gender scripts and HIV risk are influenced by culture. Participants will be heterosexual women and men between the ages of 18 and 24 currently involved in sexual relationships. At each site (New York and South Africa), 50 women and men will maintain prospective diaries over a one-month period. We will follow this period of data collection with in-depth interviews to collect narratives of their gender scripts. Analyses of these qualitative data will contribute to the final selection of preliminary items for our measures. A series of interviews and surveys will be used with large samples of women and men to establish the psychometric properties of the new methods and to test the relationships between scales, scores, and other domains of gender with HIV risk. These methods will be designed so that they can be usefully and efficiently applied in HIV prevention efforts by health, research, and education professionals as means of identifying risk among young adult women and men in heterosexual relationships.